Device for receiving radiosignals



C. BARDELONI.

DEVICE FOR RECEIVING RADIOSIGNALS. APPLICATION FILED APR. 17, 1920.

1,41 6,774., Patented May 23, 1922.

2 SHEETSSHEET I.

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C. BARDELONI.

DEVICE FOR RECEIVING RADIOSIGNALS.

APPLICATION FILED APR. 17, 1920- Patented May 23, 1922.

2 SHEETS-SHEET 21 Fly. 5.

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,cEsARr. sarennnonr, or ROME, ITALY.

Lemma.

T all whom it may concern:

Be it known that I, CESARE BARnELoNI,

V a subject of the King of Italy, residing at used for radiotelegraphic or radiotelephonic Rome, in the Kingdom of Italy, have invented certain" new and useful Improvements in Devices for Receiving Radiosignals, (for which I have filed applications in Italy January 10, 1918; Spain February 2,1920, and Denmark February 19, 1920,) of which the following is a description.

' The present invention refers to improvements in receiving methods of radiotelegraphic and radiotelephonic signals by means of ionized gas detectors with two or more electrodes subject to the action of an ionized medium, together with a contact having a rectifying action on, currents of variable direction or any :other device acting in the same manner,-both suitably arranged in oscillating circuits of the kind reception and suitably connected toconvenient sources of electric energy.

The object 2f said improvements is to utilize the ionized gas detector, as above mentioned, not only in its characteristic action as a current rectifier and amplifier, as

'well as a generator of persistent oscillations,

peculiar to such detectors, but also in such a way that the ionized gas detector and the rectifying device cooperating for the reception of" signals, differentiate their actions so 1 as to obtain in the above mentioned reception the elimination of disturbing oscillations, such as might be caused by other 1 a diotelegraphic or radiotelephonic transmissions employing a slightlydifferent wave length,or at least to lessen as much as pos{ sible the disturbances caused in the reception by atmospherical electric discharges straywaves or statics as they are called,

9 or by any other disturbing causes of electro magnetical nature. to which the receiver is re onsive, 1 v a uch a result is obta1ned,.accord1ng to the present invention, by .adding to the usual closed oscillating circuit of" the receiving 'plant to which the rectifyingcontactand the' audion grid are connected, a second closed oscillating circuit, electromagnetically or electrostatically coupled to the aerial and connected, if so required, with a second i collecting plate of'the audiom-and workiifg in such amanner'as to eliminate (whenthe second named oscillating circuit 1s COHVBII? iently'tuned) the propagation, through the DEVICE FOR RECEIVING RADIOSIGNAI LS.

1920. Serial No. 374,709.

. first collecting plate of the audion connected to the receiving telephone apparatus,,of

the disturbing currents to be excluded. The second above mentioned circuit may be regulated in such a way as either to specification of Letters Patent. 'Patented May 23, 1922., Application filed April 1-7 wholly exclude, or at least to weaken the effeet-s due to signals having a wave length greater or smaller than the one which must be received. If it is desired to exclude at the same time longer and shorter waves, two auxiliary circuits are used, ending or not in two collecting plates, and both coupled to the aerial and tuned in such a manner as to eliminate one the disturbances due to waves having a greater length and the other the disturbances due to waves of smaller length.

In the drawing attached hereto:

Fig. 1 shows schematically the electrical I connections in one of the receiving stations supplied with a rectifying contact and with the auxiliary circuit in accordance with the invention.

Figs. 2 and '3 are modifications of the ar rangement' shown at Fig. 1.

Fig. 4 shows schematically the connections when two auxiliary circuits are used.

serted a condenser 2 and an inductance'3 both adjustable at will. The aerial is inductively coupled in 4 to the inductance 10 of an oscillating closed circuit com rising the said inductance and anadjustab e condenser 11. By means of a second inductive couplingit is'then coupled in 5 to another closed oscillating circuit comprising the inductance 7. and a condenser 8 of variable capacity, The aerial through the coils of couplings4,5 is earthed at 6.

To one of the armatures'of the condenser of said second closed oscillating circuit is connectedfone of the armatures of a fixed condenser 9 the other armature of which is in communication with the grid 12 of a ther-.

the other, terminal of which is conn c ted In Fig. 1, 1 is the aerial in which are in-- gliding contact, battery closed oscillating circuitlO, 11 which will one of the plates of its and grid 12 of the audion, descent filament 14, within the first, to the aerial with a suitably-shaped conductor reaching in the ionized space of the audion, as wellsuch a manner tentials of a contrary name, tained besides setting the. rectifying detector in its right position at {10 a wave length to bring the oscillating circuit, so

65 the" lamp works only of cells 21 connected, by means of a to the positive pole of the feeds the filament. The

tery

which be hereafter called the epurator, has adjustablecondenser connected-to a collecting plate 23 placed, together with the other. cold electrode .13

and the incanthe glass bulb ,24 so'as .to receive in a direct manner a share of the stream of the electrons emanate in%)from the incandescent filament. 15

n the whole therefore the arrangement described comprises an ordinary audion receiving circuit, to which is added a second closed oscillating circuit 10, 11 coupled, like and communicating as a circuit 17, 18,119, including a current detector and rectifier suitably connected, to the circuit for the usual audion recep- 25 tion.

Upon having tuned the aerial and the oscillating circuit 7 8 for the wave length 'i zed if'the two transmissions to be received and suitably set inthe right position the rectifier and detector 19, in

, grid 12 of the audion and the conductor 23' added to "the audion may be charged to po- (which is ohby regu ing also in a convenient manner the potential upon battery 18 and potentiometer -17 In case the signals to be received be disturbed by others transmitted with oscillations of not too different from that for which the plant is tuned, it will suflice into resonance the epurating circuit 10, 11 with the disturbing oscillation and, without modifying in any way the tuning ofthe aerial, to couple it to the said circuit, through turbing influence disappears.

coupling, 4 until the dis- As is well known, theaction of the grid is to -increase the plate-current when the grid is charged to apositive'potential and to decrease this current when the potentialof the grid becomes ne ative. The lamp is worked in the range low the knee of the characteristic cul ve of the current flow- 5 5 ing between plate and filament, or, in other terms, the. ,lamp is working in the best conditions to detect an oscillating current.

Bridging the oscillating circuit connected to, 'd' and filament'isj, in my device, a rec- 6 0 tifier of alternatingcurrents, whose action is to absorbia portion or the total of the positive wave coming onto the grid from that, during the oscillation ot-=tl1e smid eircuit, the grid'of under .the influence of strong for simultaneously impinging on th that in the same instant the the negative waves, which decreases the plate-current.

When the. additional electrode is nega the "grid and the rectifier. When the" additional electrode is positively charged its effect is immaterial because it is not interposed between the filament By means of the potentiometer or the variable E. M. F. in series with therectifier', the rectifier itself canbe regulated to render the particular grid action much more one of two radio transmissions one of which is to be received, even if the tWo transmissions have the same .wave length. l I

' By means of the rectifier it is possible to increase the effect of the signals it is desi'redtoreceive, and by suitably coupling the aerial to the oscillating system, tuned to the disturbing transmission, it is p0SS1- ,ble completely to annul it.

Of course, this result is more easily realhave different wave lengths. I 7 For the above reasons, the effect of atmospheric discharges acting on the antenna and the coupled oscillating circuits of the same, oscillating period as the antenna it self, can be annulled by employing this device in the reception of radiotelegraphic and radiotelephonic signals.

However, as atmospheric discharges have not usually a constant amplitude like wireless transmisslons, it is. always possible that some of them of a yery' great strength com;

pared with the signals to be received may influence the grid, in which case the disfturbance would be reduced but not entirely ieliminated.

Should the disturbance be caused by'at- .Inospherical electrical discharges it. will be gsuflicient to tune the selecting circuit to a wave length either a little greater or a little smaller than that of the signals required and, thereon, to couple said circuit with the aerial until the disturbing influence of said discharges be attenuated as much as possible, still allowing a v y goodfreception ofthe signals. ="l- It will beseen/that the difierentiating actionwith regard to the signals exercised by the grid 12 of .ductor 23', acting together forthe elimination the audion and by the con.-

of disturbances, assisted by the selective action which is peculiar to the rectifying contact. 5

In fact the reinforcementiof the signals produced by said contact, thus inserted into the receiving circuitof the audion, is dif ferentin intensity according to the quantity 1 and the plate.

e antenna,

' of electrical oscillating energy which arrives to the contact in the unit of time. In consequence, by operating only the potentiometer 17, .it is possible to givea greater relief to a given radio transmission in comparison with two others which either owing to the length of the waves being different .from

- the former or owing to a different musical pitch, carry tothe receiving circuit of the audion aquantity of oscillating energy (for unit of time) different from-that carried by the transmission upon which the critical potential upon the rectifying contact has been-re lated. V

Just for'this reason, besides the possibility of attenuating the disturbances in the best way by making use of the device above described, said attenuation can also be securedwithout making use of conductor 23 added to the audion, by profiting by the absorbing action of the aerial produced by the epurating circuits closed on themselves (as in Fig. 1) together with the selective action of the rectifying contact. v

By. means of such arrangement it is possible, Without appreciable diminution in the intensity. of reception of the signals emitted by a given transmitting station, to eliminate the disturbing influence produced by the signals of another station transmitting at the same time, and employing, as the first, slightly damped oscillations having a wave only 4% longer or shorter than the wave for which the station is prepared.

Hence it ensues that its adoption allows of a much greater extension of the applications of radiotelegraphy, up to this time limited by the impossibility of practically eliminating the disturbances of the reception produced by ,other stations operating with only slightly damped oscillations having a wave length differing at least about 15%, though taking advantage, as far as possible, ofthe phenomena arising from the tuning of the circuits.

0f course the aforementioned percentages refer to equal quantities of electrical energy set up in the receiving aerial either from the of rather considerable power, near the receiving station,'may be inoperative'upon the aerial of the latter tuned forthe length of Wave of a distant station, when the difierfence of the two wave lengths besuch that,

for the effects of syntony, the quantities of electrical energy corresponding to them andset up contemporaneously on the receiving aerial, be about the same; a result which by themeans known up to this day was not possible to obtain.

NVith regard finally'to the disturbances originating from atmospherical electric discharges, notoriously constituted by greatly damped oscillations, their exclusion or re- K duction is yet sufficiently easy in consideration of the fact that it is not necessary to tune the epurating circuit very closely to the period for which the receiving circuit is tuned, therefore it is possible-to maintain for the signals tobe received a good intensity, practically securing .at the same time the result of rendering them less disturbed by the atmospherical dischar es.

Naturally the arrangement described and illustrated in Fig. l' is but one manner of carrying into practice the present invention,

for the same results may be obtained by arranging the various receiving and epurating devices ina way different from that already pointed'out. And thus, as shown in Fig. 2, the epurating and the receiving circuits may be connected between 25 and 22; the receiving c'rcuit further may be connected at ,6 wi the aerial circuit. 23 of the epurating circuit, instead of with in the bulb 24, can be applied also without,

adhering to the glass of'the bulb, and placed in such a way so as to directly receive through the glass the stream of the electrons emanating from the filament. t

Thus also the reinforcing circuit 17, 18, 19 can be subdivided into different sections by with condenser-9 (Fig. 3) by varying the value of the potential supplied by battery 18 through a sliding jcontact'connected to the receiving-oscillating circuit and obtaining the fractions of the voltage corresponding to one cell element by'meansof a potentiometer l7 shunted across the terminals ,of a cell element suitably connected to the feeding battery of the filament.

It is further obvious that the couplin between the epurating circuit and the aerial, instead of being. magnetic, can be electrofstatical and effected in any of the known ways. .I* Now it is finally to be considered the case that the correspondence with a given radiotelegraphic or radiotelephonic station be disturbed by twoother electromagnetical transmissions, one with a wave slightly shorter, the other with a wave slightly longer than the wave which must be received. By extending to this case theprinciple from" the others the transmission of the corresponding station, by means of two Plate 1 placing for instance, contact 19 in parallel upon which the present invention rests,- it i is possible to obtain the result of insulating 40 that the same device isalso ca parts already mediate length with the nearest longer and shorter wave,-

the nearest to the transmission wave, in a eneral way, cause the' v I By tuning the two epurating circuits, one

to the shorter and the-other to the longer disturbing waves, and by suitably coupling them to the aerial, it is possible to isolate in the. receiving circuit the wave of lnter- "It is evident that there, as a generalrule, cannot beneeded more than two epurating circuits for they, already respectively tuned and which by being -*most. considerable disturbance, said transmission wave of intermediate length will remain much better protected against the disturbing action occasionally occurring, of

other waves more atmospheric discharges generating. strongly different in length, or of damped oscillations.

All the above said about the reception pf damped oscillations applies of course, and

even more consp-icuously,

persistent oscillations as well "damped. ones.

to the receptio of disturbed by .ot er as to. the case disturbed by persistent oscillations of- "persistent oscillations Besides the above said'about the action of the device for the attenuation: of disturbing factors, it may' be not 'amissto add here ble of reinforcing the electromagnetica signals I received, for which purpose it is suflicient to reverse the action of the current rectifie 19, to adjust the potential ofbatte'ry 18, an

to tune the epurating circuit or circuits exelectronical. energy lows also actly for the oscillation which-must be received,;after having coupled them to the aerial- Therefore the arranement described althe whole utilization of the characteristical action of a usual audion detector permitting, if so required, to use the whole supplied by the incandescent filament and which ina greater or smaller partgaccording to the type of the audion employed, gets dispersed in the ordi nary ionized gas receivers.

Claims: 1. Device for receivingradiotelegraphic and. .radiotelephonic signals, comprising an I aerial, an adjustable main oscillating circuit.

ve described and &

'receivlng audion which it is sought to receive.

'tional adjustable source containin'gm lamp with a hot filament as cathode, a grid, being suitably/coupled tothe aerial, and connected at one. side tothe grid and. on the other side to the hot cathode of the lamp,

a rectifier of variable currents connected to said circuit on the same side as the 1 grid and hot cathode of the lamp, a naceiving telephone in circuit with the plate of the lamp, and an auxiliary oscillating system which is also adjustable and suitably coupled with the aerial, said system comprising means so located relatively to the lamp that the oscillations .of' said system .influence the electron stream of the lamp.

2. A device according to claim 1 wherein the auxiliary oscillating system comprises two closed oscillating circuits, both of them suitably coupled to the aerial and each one connected with an electrode adapted to-act on the electron stream of the lamp.

3. A device according to" claim 1 wherein the auxiliary oscillating system comprises an electrode 'placedQwithin the bulb of the lamp.

.4. A device-according to claim 1 comprising a potentiometer shunted across the terminals of the source of electric energy feedand a plate, said circuit ing the hot cathode ofrthe lamp and an 'addiof electromotive force 1 inserted, between the Qrectifier and the potentiometer.

5. A device according to claim 2 comprising a potentiometer shunted acrossthe terminals of the source of electric energy feeding the hot cathode of the lamp and an additional adjustable source of electromotive force inserted between the rectifier and the potentiometer. i T U 6. A device .acc rding to claiml comprising a potentiometer and an additional adjustablesource of electromotivdforce in" series with the j rectifier, the latter with its sources of potential being connected in shunt with the main oscillating circuit, and also in shunt with the circuit through the internal ionized spaceof thelampf 7 A device according to claim 2 comprising a potentiometer andtan additional adjustablesource of electromotive force in series with the rectifier, the latter with its sources of potential being connected'in shunt with the main oscillating circuit, and also in shunt with the circuit through the internal ionized space ofthe lamp.

In testimony whereof I have afiixed my signature in the presence of two witnesses, this-24th day of March, 1920.

x v "GESARE BARDELONI.

Witnesses: L A

1 Ln'rTnRN'LABoUTrA, I

Grumo GASSAGUERIJ. 

